There exists a general belief among K-16 educators as well as scientists that people must be scientifically and agriculturally literate in order to make wise and informed economic and political decisions about the use of renewable resources (Cardwell, 1994). Each State approaches Agriculture in the Classroom from the basis of its own needs and resources and is responsible for organization, funding, public outreach, materials development and teacher training (Traxler, 1990). The introduction of score-based funding as well as statewide implementation of standardized testing coupled with the ever-increasing importance of agricultural knowledge of the general population in areas with resource management issues has made the issue of agricultural education in arid regions very important. The purpose of this study was to assess the impact of various types of Agriculture in the Classroom curriculums and instruction on the agricultural arid lands literacy of 4th grade students. A pre-test/post-test analysis was administered to 21 classrooms in a Public School District in order to compare the agricultural literacy scores of students who participated in an agricultural fieldtrip experience with students who received the same materials in the form of a four-day arid lands curriculum, those who received both the field trip and curriculum, and those who did not receive any form of agricultural education module. The three treatment groups scored significantly higher on the agricultural arid lands literacy test than the control group. It was also discovered that there was no statistically significant difference between the results of three levels of treatment. However, all three treatments were statistically higher than the control group.

Rigorous statistical examination of the population dynamics of a number of long-lived perennial plant species permitted an interpretation of changes in those populations and the establishment of potentially important causal agents. Survival and recruitment of six species from the mulga-zone rangelands of Western Australia varied across three climatically different periods following the removal of domestic livestock. Two species' populations (Eragrostis xerophila and Maireana glomerifolia) had their rates of increase reduced by kangaroo and euro grazing. Both survival and recruitment of Eragrostis xerophila were reduced by this grazing while Maireana glomerifolia suffered reduced recruitment during all periods. These negative effects were most pronounced during the post-drought period of more "normal" rainfall. Three other species populations responded positively to grazing. Recruitment and survival of Eremophila spectabilis, were affected by grazing, particularly on a poor condition site, while differences in recruitment were more important for Eremophila leucophylla. Frankenia pauciflora had increased recruitment and survival during the postdrought period. The sixth species (Ptilotus obovatus) suffered increased mortality and reduced recruitment during the post-drought period. Relative rates of change in management related groups of 18 species, including the six examined in more detail, were presented as a viable addition to the analysis of trend in rangeland vegetation. Grazing by kangaroos significantly reduced the rate of recovery of destocked rangeland pastures. Site and seasonal factors affected all species populations examined. Site induced differences affected survival of all six species examined, highlighting the difficulty of replicating large scale experiments in rangeland vegetation. Different seasonal sequences (very wet, very dry, and more "normal") produced different species population responses. Populations of most species increased during the very wet, and more "normal", post-drought period, but declined, or remained static, during the drought. Potentially competitive relationships were examined at one site where the complexity of juvenile plant survival responses to seasonal conditions, treatment and to neighbor-free-space suggest potential competition, but more importantly reflect a need for more detailed study. A re-examination of Danthonia caespitosa population data collected by O.B. Williams in rangeland areas of New South Wales indicates the importance of grazing by merino sheep, seasonal conditions, and the cohort within which a plant is recruited. The extreme variability of the data highlights the need for experimental designs that take account of the frequency and importance of causal agent impact, and are related to the dynamism of the population.

Arid lands cover approximately 30% of the earth’s surface. Due to the broadness, remoteness, and harsh condition of these lands, land condition assessment and monitoring using ground-based techniques appear to be limited. Remote sensing imagery with its broad areal coverage, repeatability, cost and time-effectiveness has been suggested and used as an alternative approach for more than three decades. This thesis evaluated the potential of different remote sensing techniques for assessing and monitoring land condition of southern arid lands of South Australia. There were four specific objectives: 1) to evaluate vegetation indices derived from multispectral satellite imagery for prediction of vegetation cover; 2) to compare vegetation indices and field measurements for detecting vegetation changes and assessing land condition; 3) to examine the potential of hyperspectral imagery for discriminating vegetation components that are important in land management using unmixing techniques; and 4) to test whether spatial heterogeneity in land surface reflectance can provide additional information about land condition and effects of management on land condition. The study focused on Kingoonya and Gawler Soil Conservation Districts that were dominated by chenopod shrublands and low open woodlands over sand plains and dunes. The area has been grazed predominately by sheep for more than 100 years and land degradation or desertification due to overgrazing is evident in some parts of the region, especially around stock watering points. Grazing is the most important factor that influences land condition. Four full scenes of Landsat TM and ETM+ multispectral and Hyperion hyperspectral data were acquired over the study area. The imagery was acquired in dry seasons to highlight perennial vegetation cover that has an important role in land condition assessment and monitoring. Slope-based, distance-based, orthogonal transformation and plant-water sensitive vegetation indices were compared with vegetation cover estimates at monitoring points made by state government agency staff during the first Pastoral Lease assessments in 1991. To examine the performance of vegetation indices, they were tested at two scales: within two contrasting land systems and across broader regional landscapes. Of the vegetation indices evaluated, selected Stress Related Vegetation Indices using red, nearinfrared and mid-infrared bands consistently showed significant relationships with vegetation cover at both land system and landscape scales. Estimation of vegetation cover was more accurate within land systems than across broader regions. Total perennial and ephemeral plant cover was predicted best within land systems (R2=0.88), while combined vegetation, plant litter and soil cryptogam crust cover was predicted best at landscape scale (R2=0.39). The results of applying one of the stress related vegetation indices (STVI-4) to 1991 TM and 2002 ETM+ Landsat imagery to detect vegetation changes and to 2005 Landsat TM imagery to discriminate Land Condition Index (LCI) classes showed that it is an appropriate vegetation index for both identifying trends in vegetation cover and assessing land condition. STVI-4 highlighted increases and decreases in vegetation in different parts of the study area. The vegetation change image provided useful information about changes in vegetation cover resulting from variations in climate and alterations in land management. STVI-4 was able to differentiate all three LCI classes (poor, fair and good condition) in low open woodlands with 95% confidence level. In chenopod shrubland and Mount Eba country only poor and good conditions were separable spectrally. The application of spectral mixture analysis to Hyperion hyperspectral imagery yielded five distinct end-members: two associated with vegetation cover and the remaining three associated with different soils, surface gravel and stone. The specific identity of the image end-members was determined by comparing their mean spectra with field reflectance spectra collected with an Analytical Spectral Devices (ASD) Field Spec Pro spectrometer. One vegetation end-member correlated significantly with cottonbush vegetation cover (R2=0.89), distributed as patches throughout the study area. The second vegetation end-member appeared to map green and grey-green perennial shrubs (e.g. Mulga) and correlated significantly with total vegetation cover (R2=0.68). The soil and surface gravel and stone end-members that mapped sand plains, sand dunes, and surface gravel and stone did not show significant correlations with the field estimates of these soil surface components. I examined the potential of a spatial heterogeneity index, the Moving Standard Deviation Index (MSDI), around stock watering points and nearby ungrazed reference sites. One of the major indirect effects of watering points in a grazed landscape is the development around them of a zone of extreme degradation called a piosphere. MSDI was applied to Landsat red band for detection and assessment of these zones. Results showed watering points had significantly higher MSDI values than non-degraded reference areas. Comparison of two vegetation indices, the Normalized Difference Vegetation Index (NDVI) and Perpendicular Distance vegetation index (PD54), which were used as reference indices, showed that the PD54 was more sensitive than NDVI for assessing land condition in this perennial-dominated arid environment. Piospheres were found to be more spatially heterogeneous in land surface reflectance. They had higher MSDI values compared to non-degraded areas, and spatial heterogeneity decreased with increasing distance from water points. The study has demonstrated overall that image-based indices derived from Landsat multispectral and Hyperion hyperspectral imagery can be used with field methods to assess and monitor vegetation cover (and consequently land condition) of southern arid lands of South Australia in a quick and efficient way. Relationships between vegetation indices, end-members and field measurements can be used to estimate vegetation cover and monitor its variation with time in broad areas where field-based methods are not effective. Multispectral vegetation indices can be used to assess and discriminate ground-based land condition classes. The sandy-loam end-member extracted from Hyperion imagery has high potential for monitoring sand dunes and their movement over time. The MSDI showed that spatial heterogeneity in land surface reflectance can be used as a good indicator of land degradation. It differentiated degraded from nondegraded areas successfully and detected grazing gradients slightly better than widely used vegetation indices. Results suggest further research using these remote sensing techniques is warranted for arid land condition assessment and monitoring in South Australia. / http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1295218 / Thesis (Ph.D.) -- School of Earth and Environmental Science, 2007

abstract: Human activity has increased loading of reactive nitrogen (N) in the environment, with important and often deleterious impacts on biodiversity, climate, and human health. Since the fate of N in the ecosystem is mainly controlled by microorganisms, understanding the factors that shape microbial communities becomes relevant and urgent. In arid land soils, these microbial communities and factors are not well understood. I aimed to study the role of N cycling microbes, such as the ammonia-oxidizing bacteria (AOB), the recently discovered ammonia-oxidizing archaea (AOA), and various fungal groups, in soils of arid lands. I also tested if niche differentiation among microbial populations is a driver of differential biogeochemical outcomes. I found that N cycling microbial communities in arid lands are structured by environmental factors to a stronger degree than what is generally observed in mesic systems. For example, in biological soil crusts, temperature selected for AOA in warmer deserts and for AOB in colder deserts. Land-use change also affects niche differentiation, with fungi being the major agents of N2O production in natural arid lands, whereas emissions could be attributed to bacteria in mesic urban lawns. By contrast, NO3- production in the native desert and managed soils was mainly controlled by autotrophic microbes (i.e., AOB and AOA) rather than by heterotrophic fungi. I could also determine that AOA surprisingly responded positively to inorganic N availability in both short (one month) and long-term (seven years) experimental manipulations in an arid land soil, while environmental N enrichment in other ecosystem types is known to favor AOB over AOA. This work improves our predictions of ecosystem response to anthropogenic N increase and shows that paradigms derived from mesic systems are not always applicable to arid lands. My dissertation also highlights the unique ecology of ammonia oxidizers and draws attention to the importance of N cycling in desert soils. / Dissertation/Thesis / Ph.D. Biology 2013

Il cambiamento climatico e la pressione antropica sulle risorse idriche rendono le politiche di gestione dell’acqua primordiali nell'agenda dei policy makers. Nel mio lavoro, inizialmente, presento una rassegna della letteratura in materia di modelli di Equilibro Generale Calcolabile (CGE) che incorporano l’acqua. In tale ambito, propongo la seguente classificazione: (i) la concorrenza tra i settori per l’uso di acqua; (ii) le politiche di prezzo e delle tariffe sull’acqua, (iii) l'acqua e le questioni commerciali, (iv) i modelli CGE ed altri modelli. In secondo luogo, analizzo gli effetti della siccità per l'economia del Kenya attraverso un modello CGE statico, calibrato sulla Matrice di Contabilità Sociale (SAM) del Kenya (2003). Il Kenya è stato scelto perché Paese particolarmente esposto a ricorrenti siccità (ad esempio negli anni 1994, 1998-2000, 2001 e 2003) che hanno duramente colpito le popolazioni più vulnerabili del paese, cioè quelle concentrate nelle zone aride e semiaride (ASAL). Inoltre, propongo l'introduzione di schemi di tassazione, al fine di produrre un extra-reddito che possa essere reinvestito per aumentare l'efficienza del settore idrico in Kenya o per trasferimenti alle famiglie rurali più povere. Infine, riproduco l'attuazione del progetto “Arid Land and Resource Management Project” (ALRMP) di FAO e Banca Mondiale. I risultati mostrano che, in primo luogo, gli effetti di una riduzione della dotazione di acqua sono più robusti di quelli derivanti da un aumento della dotazione d'acqua. In secondo luogo, la simulazione di uno scenario di siccità - in cui non solo la dotazione di acqua, ma anche la disponibilità di terra e la produttività di attività selezionate sono ridotti - fornisce un quadro più coerente dei risultati. In terzo luogo, tassare “raw water” (il fattore di acqua) può influenzare negativamente i redditi degli abitanti delle zone rurali. Infine, Il ALRMP ha un impatto positivo sulla riduzione degli effetti negativi della siccità sulle ASAL in Kenya. / Climate change and human pressure on water resources make water management policies primordial in the agenda of policy makers. I first propose a literature review of the works on Water Computable General Equilibrium (CGE) Models suggesting the following classification: (i) competition between sectors; (ii) water pricing policies and tariffs; (iii) water and trade issues; (iv) CGE and other models. Secondly, the effects of droughts on the Kenyan economy are studied by means of a static CGE model, calibrated on the 2003 Social Accounting Matrix (SAM) of Kenya. As a water scarce Sub-Saharan country, Kenya is among those countries considered particularly exposed to drought problems. This has been witnessed in recent years by several recurring droughts (1994, 1998-2000, 2001, and 2003) which have harshly hit the most vulnerable part of the country, namely the Arid and Semi Arid Lands (ASAL). Besides, I propose the introduction of several taxation schemes in order to produce an extra revenue to be either reinvested in increasing the efficiency of the water sector in Kenya, or redistributed to the poorest rural households. Finally we simulate the implementation of the UN-FAO and World Bank “Arid Land and Resource Management Project” (ALRMP). The results show that, firstly, the effects of reducing water endowment are stronger than when increasing water endowment. Secondly, simulating a drought scenario – where not just water endowment but also availability of land and the productivity of selected activities are reduced - gives a more coherent picture of the outcomes. Thirdly, taxing raw water (the water factor) may negatively affect rural dwellers as they are owners of water resources. Finally, I found that the ALRMP has a positive impact on mitigating the negative effects of droughts in Kenyan ASAL.